Philipp Tschandl

Accuracy in melanoma detection: A 10-year multicenter survey

BACKGROUND Early excision is the only strategy to reduce melanoma mortality, but unnecessary excision of benign lesions increases morbidity and healthcare costs. OBJECTIVE To assess accuracy in melanoma detection based on number-needed-to-excise (NNE) values over a 10-year period. METHODS Information was retrieved on all histopathologically confirmed cutaneous melanomas or melanocytic nevi that were excised between 1998 and 2007 at participating clinics. NNE values were calculated by dividing the total number of excised lesions by the number of melanomas. Analyses included changes in NNE over time, differences in NNE between specialized clinical settings (SCS) versus non-specialized clinical settings (NSCS), and patient factors influencing NNE. RESULTS The participating clinics contributed a total of 300,215 cases, including 17,172 melanomas and 283,043 melanocytic nevi. The overall NNE values achieved in SCS and NSCS in the 10-year period were 8.7 and 29.4, respectively. The NNE improved over time in SCS (from 12.8 to 6.8), but appeared unchanged in NSCS. Most of the effect on NNE in SCS was due to a greater number of excised melanomas. Higher NNE values were observed in patients younger than 40 years and for lesions located on the trunk. LIMITATIONS No data concerning the use of dermatoscopy and digital monitoring procedures were collected from the participating centers. CONCLUSION Over the 10-year study period, accuracy in melanoma detection improved only in specialized clinics maybe because of a larger use of new diagnostic techniques such as dermatoscopy.

Diagnostic accuracy of dermatoscopy for melanocytic and nonmelanocytic pigmented lesions.

BACKGROUND It is unknown whether dermatoscopy improves the diagnostic accuracy for all types of pigmented skin lesions or only for those that are melanocytic. OBJECTIVE We sought to assess if the addition of dermatoscopy to clinical examination with the unaided eye improves diagnostic accuracy for all types of pigmented lesions. METHODS We analyzed 463 consecutively excised pigmented skin lesions collected during a period of 30 months in a primary care skin cancer practice in Queensland, Australia. RESULTS Of 463 lesions, 217 (46.9%) were nonmelanocytic. Overall 30% (n = 138) were malignant including 29 melanomas, 72 basal cell carcinomas, and 37 squamous cell carcinomas. The diagnostic accuracy for malignant neoplasms measured as area under receiver operating characteristic curves was 0.89 with dermatoscopy and 0.83 without it (P < .001). Given a fixed specificity of 80%, the corresponding sensitivity was 82.6% with dermatoscopy and 70.5% without it. The improvement achieved by dermatoscopy was higher for nonmelanocytic lesions than for melanocytic lesions. A short algorithm based on pattern analysis reached a sensitivity of 98.6% for basal cell carcinoma, 86.5% for pigmented squamous cell carcinoma, and 79.3% for melanoma. Among benign conditions, the highest false-positive rate (90.5%) was observed for lichen planus-like keratosis. LIMITATIONS Estimates of diagnostic accuracy are influenced by verification bias. CONCLUSIONS Dermatoscopy improves the diagnostic accuracy for nonmelanocytic lesions. A simple algorithm based on pattern analysis is suitable for the detection of melanoma and nonmelanoma skin cancer.

Dermatoscopy of pigmented Bowen's disease

BACKGROUND Pigmented Bowens disease is not well characterized. OBJECTIVE To characterize the clinical and dermatoscopic appearance of pigmented Bowens disease. METHODS We performed a retrospective analysis of 52 consecutive cases of pigmented Bowens disease. RESULTS Of 951 histopathologically verified cases of Bowens disease that underwent biopsy during the study period, 52 (5.5%) were pigmented. Dermatoscopically pigmented Bowens disease is typified by a pattern of dots and/or structureless zones. In 21.2% (n=11), we observed brown or gray dots arranged in a linear fashion. Vessels were identified in 67.3% of lesions with a predomination of coiled vessels. A linear arrangement of vessels was seen in 11.5%. LIMITATIONS Conclusions are limited by the fact that this was a retrospective, uncontrolled study. CONCLUSIONS Pigmented Bowens disease has a characteristic dermatoscopic pattern. Linear arrangement of brown and/or gray dots and/or coiled vessels is a specific clue to pigmented Bowens disease.

NRAS and BRAF Mutations in Melanoma-Associated Nevi and Uninvolved Nevi

According to the prevailing multistep model of melanoma development, oncogenic BRAF or NRAS mutations are crucial initial events in melanoma development. It is not known whether melanocytic nevi that are found in association with a melanoma are more likely to carry BRAF or NRAS mutations than uninvolved nevi. By laser microdissection we were able to selectively dissect and genotype cells either from the nevus or from the melanoma part of 46 melanomas that developed in association with a nevus. In 25 cases we also genotyped a control nevus of the same patients. Available tissue was also immunostained using the BRAFV600E-mutation specific antibody VE1. The BRAFV600E mutation was found in 63.0% of melanomas, 65.2% of associated nevi and 50.0% of control nevi. No significant differences in the distribution of BRAF or NRAS mutations could be found between melanoma and associated nevi or between melanoma associated nevi and control nevi. In concordant cases immunohistochemistry showed a higher expression (intensity of immunohistochemistry) of the mutated BRAFV600E-protein in melanomas compared to their associated nevi. In this series the presence of a BRAF- or NRAS mutation in a nevus was not associated with the risk of malignant transformation. Our findings do not support the current traditional model of stepwise tumor progression.

Dermatoscopy of flat pigmented facial lesions

The diagnosis of flat pigmented lesions on the face is challenging because of the morphologic overlap of biologically different lesions and the unknown significance of dermatoscopic patterns.

Dermoscopy and entomology (entomodermoscopy)

Although dermoscopy has been primarily designed for aiding the in vivo diagnosis of skin tumors, recent advances indicate it is also useful in the diagnosis of common skin infections and infestations. As such, dermoscopy connects the research fields of dermatology and entomology into one field of “entomodermoscopy”. In this article we give an overview on the current applications of entomodermoscopy.

Dermoscopic clues to differentiate facial lentigo maligna from pigmented actinic keratosis

Dermoscopy is limited in differentiating accurately between pigmented lentigo maligna (LM) and pigmented actinic keratosis (PAK). This might be related to the fact that most studies have focused on pigmented criteria only, without considering additional recognizable features.

Growth rate of melanoma in vivo and correlation with dermatoscopic and dermatopathologic findings.

Objectives: The aim of this study was to calculate the horizontal growth rate of melanoma in vivo and to correlate it with morphologic findings. Patients and Methods: We searched our database for melanomas for which sequential dermatoscopic images and histopathologic slides were available. The final sample consisted of 50 melanomas of 48 patients (mean age: 50 ± 15 years, 62% females). We calculated the horizontal growth rate in mm2 per year by morphometric analysis of digital dermatoscopic images. Dermatoscopic and dermatopathologic findings were assessed according to predefined criteria and correlated with the horizontal growth rate. Results: The median time interval between baseline and follow-up image was 12 months (range: 2–100 months). The majority of melanomas were in situ (n=28, 56%). The mean horizontal growth rate of all melanomas was 5.3 mm2/year (SD: ± 5.8 mm2/year). The histopathologic findings of numerous and large epidermal nests were associated with rapid growth. This histopathologic pattern corresponded to a pattern of clods (“globules”) dermatoscopically. From a dermatoscopic point of view, melanomas with a main pattern of clods grew significantly faster (mean horizontal growth rate: 10.4 mm2/year, 95% CI: 6.4-14.4 mm2/year) than melanomas with mainly a reticular pattern (4.8 mm2/year, 95% CI: 2.7–7.0 mm2/year) or with other patterns (2.6 mm2/year, 95% CI: −0.5–5.6 mm2/ year, p=0.01). Conclusion: Morphologic characteristics of melanoma are associated with biologic behavior. Large and numerous epidermal nests (corresponding to a pattern of clods dermatoscopically) indicate more rapid growth.

The BRAAFF checklist: a new dermoscopic algorithm for diagnosing acral melanoma

The parallel ridge pattern (PRP) is considered the dermoscopic hallmark of acral melanoma (AM). However, it was recently shown that approximately one‐third of AMs do not display a PRP dermoscopically, rendering their detection more troublesome.

Prediction without Pigment: a decision algorithm for non-pigmented skin malignancy

While there are several published comprehensive stepwise algorithmic methods for diagnosing pigmented skin malignancy, only limited material has been published for the stepwise assessment of non-pigmented lesions. We present a method based on pattern analysis, with a stepwise assessment, first, for ulceration, second, for white clues (defined as white lines, or in the case of a raised lesion any of the keratin clues: dermatoscopic white circles, dermatoscopic white structureless areas or surface keratin), and third, if no ulceration or white clues are present, proceed to vessel pattern analysis. This is a novel method, and apart from the assessment of white clues in raised lesions, it has not been formally tested. The priority of keratin clues in raised lesions over vessel pattern analysis has, however, been verified. It is conceded that this method is less specific than methods which have clues of pigmented structures, and accepting these limitations, Prediction without Pigment is a decision algorithm intended to guide the clinician in the decision as to whether to perform a biopsy rather than consistently leading to a specific diagnosis. Reaching a more specific diagnosis at the end of our flowchart can be achieved by weighing of clues both clinical and dermatoscopic, and that ability can be expected to improve with both knowledge and experience, but no diagnostic method, including this one, can be 100% sensitive in diagnosing malignancy, in particular, melanoma. Taking these limitations into account, any non-pigmented lesion, regardless of pattern analysis, which is raised and firm (nodular) and for which a confident, specific benign diagnosis cannot be made, should be excised to exclude the nodular variant of amelanotic melanoma.